Xerostomia is a common consequence of radiotherapy in head and neck cancer. The objective was to compare the regional radiation dose distribution in patients that developed xerostomia within 6 months of radiotherapy and those recovered from xerostomia within 18 months post-radiotherapy. We developed a feature generation pipeline to extract dose volume histogram features from geometrically defined ipsilateral/contralateral parotid glands, submandibular glands, and oral cavity surrogates for each patient. Permutation tests with multiple comparisons were performed to assess the dose difference between injury vs. non-injury and recovery vs. non-recovery. Ridge logistic regression models were applied to predict injury and recovery using clinical features along with dose features (D10-D90) of the subvolumes extracted from oral cavity and salivary gland contours + 3 mm peripheral shell. Model performances were assessed by the area under the receiver operating characteristic curve (AUC) using nested cross-validation. We found that different regional dose/volume metrics patterns exist for injury vs. recovery. Compared to injury, recovery has increased importance to the subvolumes receiving lower dose. Within the subvolumes, injury tends to have increased importance towards D10 from D90. This suggests that different threshold for xerostomia injury and recovery. Injury is induced by the subvolumes receiving higher dose, and the ability to recover can be preserved by further reducing the dose to subvolumes receiving lower dose.

Background: Angiotensin-converting enzyme 2 (ACE2), a primary component of the vasoprotective axis in the renin-angiotensin system (RAS), has recently been found to have regulatory actions in hypoxic pulmonary hypertension and monocrotaline-induced pulmonary hypertension. We explored the hypothesis that the level of ACE2 protein contents may be decreased in patients with pulmonary arterial hypertension (PAH) due to congenital heart disease (CHD). Objective: We observed the serum ACE2 protein contents in patients with PAH due to CHD (CHD-PAH), and investigated their correlation with mean pulmonary arterial pressure (mPAP). Methods: One hundred and four patients with CHD and 33 normal control patients (group A) were involved in the research. The patients with CHD were divided into 55 cases of nonpulmonary hypertension (group B), 25 cases of mild to moderate pulmonary hypertension (group C) and 24 cases of severe pulmonary hypertension (group D). The serum level of ACE2 protein contents were detected by enzyme-linked immunosorbent assay (ELISA), and the relationship between these contents and mPAP were analyzed. Results: ACE2 protein contents significantly declined as mPAP increased. The mPAP was negatively correlated with the level of ACE2 protein contents. Conclusions: These results demonstrated that ACE2 may play an important regulatory role in CHD-PAH.

Radiation-induced xerostomia is one of the most prevalent symptoms during and after head and neck cancer radiation therapy (RT). We aimed to discover the spatial radiation dose-based (voxel dose) importance pattern in the major salivary glands in relation to the recovery of xerostomia 18 months after RT, and to compare the recovery voxel dose importance pattern to the acute incidence (injury) pattern. Methods and Materials: This study included all patients within our database with xerostomia outcomes after completion of curative intensity modulated RT. Common Terminology Criteria for Adverse Events xerostomia grade was used to define recovered versus nonrecovered group at baseline, between end of treatment and 18 months post-RT, and beyond 18 months, respectively. Ridge logistic regression was performed to predict the probability of xerostomia recovery. Voxel doses within geometrically defined parotid glands (PG) and submandibular glands (SMG), demographic characteristics, and clinical factors were included in the algorithm. We plotted the normalized learned weights on the 3-dimensional PG and SMG structures to visualize the voxel dose importance for predicting xerostomia recovery. Results: A total of 146 head and neck cancer patients from 2008 to 2016 were identified. The superior region of the ipsilateral and contralateral PG was the most influencial for xerostomia recovery. The area under the receiver operating characteristic curve evaluated using 10-fold cross-validation for ridge logistic regression was 0.68 AE 0.07. Compared with injury, the recovery voxel dose importance pattern was more symmetrical and was influenced by lower dose voxels. Conclusions: The superior portion of the 2 PGs (low dose region) are the most influential on xerostomia recovery and seem to be equal in their contribution. The dissimilarity of the influence pattern between injury and recovery suggests different underlying

Level III.

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Level III.

Objective This study was performed to investigate the correlation between pulmonary dysfunction patterns and diaphragmatic sagittal rotation in patients with ankylosing spondylitis accompanied by kyphosis. Methods Thirty patients (27 male, 3 female) with kyphotic deformity secondary to ankylosing spondylitis underwent pedicle subtraction osteotomy and were retrospectively reviewed. All patients had undergone preoperative computed tomography with three-dimensional reconstruction, full-length spine radiographs, and pulmonary function tests. The diaphragmatic angle in the median sagittal plane (DA), pulmonary function test results, and radiological parameters were studied. Results Correlation coefficients were used to present the correlation between the DA and pulmonary function and the global kyphosis (GK), respectively. The data analysis presented positive correlations between the DA value and vital capacity (VC), forced vital capacity (FVC), expiratory reserve volume (ERV), inspiratory reserve volume (IRV) and peak expiratory flow (PEF). There was likewise a negative correlation between DA value and the global kyphosis (GK). Additionally, there were further significantly statistical improvements for DA, ERV, IRV, FVC, and VC, PEF, postoperatively. Conclusions Except for the restriction of the chest wall motion and the abnormalities of lung parenchyma, the diaphragmatic sagittal rotation is also an influencing factor of pulmonary dysfunction in patients with ankylosing spondylitis accompanied by kyphosis.